Chapter 17 - Section 17.3 - Study Guide - Assess Your Learning Outcomes - Page 669: 5

The adrenal glands are small, triangular-shaped endocrine glands located on top of each kidney. They play a crucial role in producing various hormones that regulate different physiological processes in the body. The adrenal glands are divided into two main regions: the adrenal cortex and the adrenal medulla. These regions have distinct structures and functions. **Anatomy of the Adrenal Glands:** 1. **Adrenal Cortex:** This is the outer layer of the adrenal gland and comprises about 80-90% of the gland's mass. It is further subdivided into three distinct zones, each responsible for producing specific types of hormones. - **Zona Glomerulosa:** This outermost layer produces mineralocorticoids, primarily aldosterone. Aldosterone helps regulate electrolyte balance, particularly sodium and potassium, and plays a role in maintaining blood pressure and fluid balance. - **Zona Fasciculata:** This middle layer produces glucocorticoids, mainly cortisol. Cortisol is involved in regulating metabolism, immune responses, and stress reactions. It helps the body manage stress and maintain energy levels. - **Zona Reticularis:** This innermost layer produces androgens, which are male sex hormones that are also present in females. These hormones have various effects on sexual development and libido. 2. **Adrenal Medulla:** This is the innermost part of the adrenal gland, surrounded by the adrenal cortex. The medulla is responsible for producing two main hormones: epinephrine (adrenaline) and norepinephrine (noradrenaline). These hormones are part of the body's "fight or flight" response to stress. They increase heart rate, dilate airways, and divert blood flow to the muscles, preparing the body for quick and intense physical action. **Structural Differences between Cortex and Medulla:** 1. **Cell Types:** - The adrenal cortex consists of specialized cells that are organized into the three zones mentioned earlier: glomerulosa, fasciculata, and reticularis. - The adrenal medulla is composed of chromaffin cells, which are specialized neuroendocrine cells derived from the same embryonic tissue as sympathetic nervous system neurons. 2. **Hormone Production:** - The adrenal cortex produces a variety of steroid hormones, including aldosterone, cortisol, and androgens. - The adrenal medulla produces catecholamines, such as epinephrine and norepinephrine. 3. **Function:** - The adrenal cortex hormones are involved in various regulatory processes, including electrolyte balance, metabolism, and immune responses. - The adrenal medulla hormones are responsible for the rapid physiological responses seen during the "fight or flight" reaction. They prepare the body for emergency situations by increasing heart rate, dilating airways, and redirecting blood flow. In summary, the adrenal glands consist of two main regions: the cortex, which produces various steroid hormones, and the medulla, which produces adrenaline and noradrenaline for immediate stress responses. Each region has distinct structures and functions that contribute to the overall function of the adrenal glands in maintaining homeostasis and responding to stress.

The adrenal glands are small, triangular-shaped endocrine glands located on top of each kidney. They play a crucial role in producing various hormones that regulate different physiological processes in the body. The adrenal glands are divided into two main regions: the adrenal cortex and the adrenal medulla. These regions have distinct structures and functions. **Anatomy of the Adrenal Glands:** 1. **Adrenal Cortex:** This is the outer layer of the adrenal gland and comprises about 80-90% of the gland's mass. It is further subdivided into three distinct zones, each responsible for producing specific types of hormones. - **Zona Glomerulosa:** This outermost layer produces mineralocorticoids, primarily aldosterone. Aldosterone helps regulate electrolyte balance, particularly sodium and potassium, and plays a role in maintaining blood pressure and fluid balance. - **Zona Fasciculata:** This middle layer produces glucocorticoids, mainly cortisol. Cortisol is involved in regulating metabolism, immune responses, and stress reactions. It helps the body manage stress and maintain energy levels. - **Zona Reticularis:** This innermost layer produces androgens, which are male sex hormones that are also present in females. These hormones have various effects on sexual development and libido. 2. **Adrenal Medulla:** This is the innermost part of the adrenal gland, surrounded by the adrenal cortex. The medulla is responsible for producing two main hormones: epinephrine (adrenaline) and norepinephrine (noradrenaline). These hormones are part of the body's "fight or flight" response to stress. They increase heart rate, dilate airways, and divert blood flow to the muscles, preparing the body for quick and intense physical action. **Structural Differences between Cortex and Medulla:** 1. **Cell Types:** - The adrenal cortex consists of specialized cells that are organized into the three zones mentioned earlier: glomerulosa, fasciculata, and reticularis. - The adrenal medulla is composed of chromaffin cells, which are specialized neuroendocrine cells derived from the same embryonic tissue as sympathetic nervous system neurons. 2. **Hormone Production:** - The adrenal cortex produces a variety of steroid hormones, including aldosterone, cortisol, and androgens. - The adrenal medulla produces catecholamines, such as epinephrine and norepinephrine. 3. **Function:** - The adrenal cortex hormones are involved in various regulatory processes, including electrolyte balance, metabolism, and immune responses. - The adrenal medulla hormones are responsible for the rapid physiological responses seen during the "fight or flight" reaction. They prepare the body for emergency situations by increasing heart rate, dilating airways, and redirecting blood flow. In summary, the adrenal glands consist of two main regions: the cortex, which produces various steroid hormones, and the medulla, which produces adrenaline and noradrenaline for immediate stress responses. Each region has distinct structures and functions that contribute to the overall function of the adrenal glands in maintaining homeostasis and responding to stress.